In the centre of each tooth, under the outer layers of enamel and dentine, is a collection of nerves and blood vessels called the dental pulp. The vessels of the pulp enter the tooth through a hole in the root tip, or root apex, and run along the root canal to a space in the centre of the tooth crown called the pulp cavity, or chamber.
This is a companion discussion topic for the original article at https://patient.info/oral-dental-care/toothache/root-canal-treatments